21501023134406 has 4 divisors (see below), whose sum is σ = 32251534701612. Its totient is φ = 10750511567202.

The previous prime is 21501023134391. The next prime is 21501023134477. The reversal of 21501023134406 is 60443132010512.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5375255783600 + ... + 5375255783603.

It is an arithmetic number, because the mean of its divisors is an integer number (8062883675403).

Almost surely, 2^{21501023134406} is an apocalyptic number.

21501023134406 is a deficient number, since it is larger than the sum of its proper divisors (10750511567206).

21501023134406 is a wasteful number, since it uses less digits than its factorization.

21501023134406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10750511567205.

The product of its (nonzero) digits is 17280, while the sum is 32.

Adding to 21501023134406 its reverse (60443132010512), we get a palindrome (81944155144918).

The spelling of 21501023134406 in words is "twenty-one trillion, five hundred one billion, twenty-three million, one hundred thirty-four thousand, four hundred six".